While you may know that gut health is central to good digestion, you may not have known that the gut affects nearly EVERY system in the body and plays a significant role in how they all function. You may have even heard that your gut is responsible for immune health and that it is the “second brain!” Also true! As we enter cold and flu season, it’s an ideal time to inform you about how important overall gut health is for a healthy immune response and overall good health!
When people say 70 to 80% of our immune system resides in our gut, what does that mean?
First, your immune system initiates an immune response against harmful things such as viruses, bacteria, stress, inflammation or an unhealthy diet. For example, when you have a sore throat (caused by an invading virus or bacteria), your immune system realizes there’s something wrong and that you need specialized white blood cells (macrophages), which are made in your lymph nodes, to fight it off. As a result, your lymph glands swell up. That is your immune system at work.
Immunoglobulins (antibodies) like IgA, IgG and IgM are made in our gut from various amino acids. Immunoglobulins are secreted from the gut lining in direct response to inflammation. For example, IgA is made from glutamine, which is an amino acid that we get in our diet. The lining of the intestines secretes IgA in response to inflammation, to keep it under control. Inflammation could be caused by repetitive antibiotic use, food allergies, a high-sugar diet and/or stress, to name just a few. You can go years without any kind of outward symptoms of gut problems because this built-in system keeps inflammation at bay.
A stool analysis can be used to measure levels of Immunoglobulin A to determine gut health. High levels of IgA discovered by this testing will indicate that there’s an acute problem that needs to be solved. However, in a chronic situation, the IgA will become depleted.
What exactly is “leaky gut?”
A fancier phrase for leaky gut is “intestinal permeability.” The lining of the intestines is formed by cells called “tight junction cells,” which interlock and fit together very tightly to form a barrier. When you have inflammation in the gut, this lining becomes so thin, cracks form between the cells—creating an environment where bad stuff (bacteria, viruses, etc.) can get in, and good stuff can escape! An inflamed gut can lead to the loss of important micronutrients such as vitamins, minerals, amino acids, essential fatty acids and antioxidants, thus preventing the body from absorbing them and using them to maintain good health.
Examples of nutrients that have been identified as critical for the growth and function of immune cells include vitamin C, vitamin D, zinc, selenium, iron and protein (including the amino acid glutamine). Whether obtained through diet or taken as supplements, these micronutrients will not strengthen the immune system if the gut is in disrepair. Think of a bucket with a hole in it. You can add water to the bucket but if there is a hole, the water will leak out and not fill the bucket. In other words, you can take supplements every day, but if your gut isn’t absorbing them, you’re wasting your money and compromising your health!
Why is the gut called “the second brain?”
When the immune system is weakened by what’s going on in the gut, it can present different symptoms, but it usually can be linked with mental health. The neurotransmitters in our brain like dopamine, serotonin, GABA and glutamate are all made from amino acids that we get every day in our diet.
Consider serotonin, which is our “happy” neurotransmitter. It’s what controls our mood and ability to feel stable and joyful. Symptoms of low serotonin are depression and anxiety. Serotonin is made from tryptophan, which is an amino acid that’s found in all meats and dairy products. Even if you’re eating the appropriate foods (or taking supplements) and getting plenty of tryptophan, that tryptophan must convert in the gut to another amino acid, 5-HTP. Once it’s absorbed from the gut into the bloodstream, 5-HTP is the precursor that allows the body to make serotonin.
If you have a gut in disrepair, the 5-HTP can leak out of the gut before it can get into the bloodstream. So now you have a neurotransmitter imbalance, which affects behavioral and or mental health. Therefore, you must fix the gut first to rebalance neurotransmitters.
What are the best ways to protect gut health?
We must protect the gut microbiome (the good and bad bacteria in our gut) to have the best gut health. Many people think the gut microbiome is in the stomach, but it is actually located in the large and small intestine. It not only contains beneficial and harmful bacteria but also microbes made up of fungi, yeast and viruses. There are roughly 100 trillion microbes inside the human body with the vast majority residing in our gut. We consume them daily through the food and water we ingest. The factors that affect our gut microbiome balance are diet, infections, medications and chronic stress (mental or physical).
A diet that includes a variety of fruits, vegetables, fermented foods and fiber all contribute to microbial diversity and improve the gut microbiome. This can also be accomplished by taking a good prebiotic/probiotic, but diet is preferred over supplements whenever possible. Prebiotics are found naturally in artichokes, apples and green bananas. In addition to the diet mentioned above, it is crucial to gut health to avoid refined processed foods including sugar, high fructose corn syrup and GMO foods. It is also important to note that the top five most gut inflammatory foods are gluten, cow’s dairy, eggs, soy and peanuts. If the diet has an abundance of any of these, there will generally be associated gut inflammation.
Lifestyle changes for gut health
While sometimes antibiotics cannot be avoided, it is well documented that they destroy not only the pathogens they are meant to eradicate but also attack and destroy the good bacteria in our gut. Take antibiotics sparingly and be mindful about replenishing the gut afterwards. The two most prevalent beneficial gut bacteria are Lactobacillus and Bifidobacterium so if a probiotic supplement is chosen, it should include multiple strains of each of these species.
Reducing stress is paramount to overall gut health. This includes managing psychological, physical and metabolic stress. Relaxation techniques like deep breathing help lower stress and anxiety as well as regular physical activity, exercise and making sleep a priority.
A chronically inflamed gut always results in a compromised or inefficient immune response so illnesses can last longer and be more severe. When we have a healthy gut, we have a healthy immune system that is tolerant to a variety of conditions. Therefore, having a balanced immune system is essential for optimal health!
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